Sash balancing construction



Mardi 15, 1938v A. scHNlTzLER SASH BALANCING CONSTRUCTION Filed Aug. 6, 1932 lilllIlI llllllllllrlllllll'll llllllllll Patented Mar. l5, 1938 AUNITE STAES PATENT GFFICE SASH BALANOING CONSTRUCTION Abraham Schnitzler, Chelsea, Mass. Application August 6, 1932, Serial No. 627,795 15 Claims. (Cl. 292-79) This invention relates generally to window conspring pressure resulting from engagement of struction wherein the window sash is designed the member with spaced portions of the ramp, to slide freely to open and closed positions, as so as to cause the member to exert substantialwell as to be held in any desired open position, ly the same lifting or counter-balancing presand particularly to an improved sash holding sure on the sash notwithstanding different ver- 5 and balancing mechanism. tical adjustments of the sash. The mechanism Among the objects of the present invention may be adjusted to exert any desired pressure is the provision of a window construction Where- Within a predetermined range t0 enable the in the sash: is easily raised or lowered; is held same to be used with a variety of sash weights tight and without rattling in all positions; can end SiZeS, SO that, if desired, ell SeSlieS may be 10 be easily and quickly mounted in the window formed with like grOOVeS 0r rernPS- The meehrame and removed therefrom; and can be readanism is arranged t0 enable the Seme t0 be ed ily counter-balanced to the desired extent withjusted Without requiring its removal er the reout being removed from the window frame. Gthmoval of the sash, and t0 be rendered inoperaer objects are to provide an improved sash-holdtive when installation or removal of the sash is 15 ing mechanism which is simple, sturdy, and desired. compact; which can be installed with minimum With the foregoing and other obJ'eCtS and fee* labor as a unit in the window frame; and which tures in View, I Shell 110W deerilte my inVenneed not be removed from the window frame in tiOn in eenjunetin With en embodiment therethe event that removal of the sash is necessary Of Sli-0WD in the eCCOrnpenying drawing, wherein 20 or that the mechanism is to be adjusted to vary Figure 1 iS a frOnt VieW 0f e WindOW WllOSe 10W'- its counter-balancing force on the sash. The er sash is equipped With the holding rneGlleIiiSrn sash-hairline mechanism which I have devised of the present invention, eert 0f the Window is generally oi the type comprising a roller, which frame and Sash being brOken away rides in a groove in the stile edge of the sash Figure 2 iS 'en eleVetiOn 0f en installed hold- 25 and which is yieldingly and tightly engaged in ing mechanism looking in the direction of the the groove by spring .action for all positions of veL-rrOWS 2-2 SllOWn in Figure 1- the sash. Figure 3 represents a section on the vline 3--3 Another object of the invention resides in the 0i Figure 2, and includes an upper Corner 0f 3o provision of means for affording a substantially the Sash in fully lOWered DOSitOn- 30 constant sash counter-balancing force for the Figure l iS e VieW Similar t0 Figure 3, but With various positions of adjustment of the sash, so tl'lel SeSh in fully reieed DOSitiOnthat the effort exerted in raising the sash from Figure 5 is a fragmentary perspective 0f the any point need be substantially no greater than Sash with e stile groeve exposed t0 viewfrom any other point. Figure 6 is a detail perspective, showing the 35 It is a further object of the invention te proaccessibility of the sash-holding mechanism for vide means having the aforesaid uniform counadjustment Durp0SeS- ter-balancing function and serving also to yield- My invention is illustrated in Figure 1 as apably hold the sash in the desired position in plied. to the lower window sash of a conventional 40 the window frame. window structure, but it will, of course, be under- 40 It is also an object of the invention to pro- StOOd that it Cen bev eInbOdied equally eS Well vide simple and readily accessible and operin the upper WindOW Sash and irl other Window able means for retracting the counter-balancing StruCtn-res. AS best ShOWn in this ligure, the means and holding the same retracted to enable lOWer Sash i is mounted fOr ulOWerd end downa sash constructed in accordance with the in- Ward sliding movement in suitable ways defined, 45 vention to be readily removed irom and placed as ordinarily, by Suitable guide Strips eSteneCl in the window frame. to the jambs 2` of the window frame. The sash- In accordance with the general features of holding mechanism of the prese-nt invention inthe invention, the counter-balancing instrumencludes an anchor plete 3, Wlreli, eS Shown, iS 0f talities include a spring arranged to press a elongated rectangular form and can be secured 50 sash engaging member in a ramp or tapered near its upperI and lower edges, as by screws 4, groove bottom of the sash stile so as to exert an to each of the jambs 2. To this end, a suitable upward thrust on the sash to overcome gravity. opening is formed through each jamb, so that A connection between the spring and sash enthe mechanism on the back of the plate 3 may gaging member compensates for diiierences in occupy the usual hollow space 5 in back oi the 55 jamb. The edge portions 6 of the jamb bordering the jamb opening may be countersunk sufficiently so that the outer or front face of the plate 3 merges with and constitutes part of the flat surface against which a stile edge of the sash bears. A bell crank 'i is pivotally secured as by a pin 3 to suitably spaced brackets S, lwhich may be affixed as by screws l@ somewhat above the lower end of the plate 3. The lower end portion of the crank 'i is bifurcated at il and supports a stud I2 on which a roller i3 is rotatably mounted against lateral movement between the fork elements. The upper end of the crank 'I is pivotally secured, as at ifi, to the lower end of a rod l5, whose upper end portion passes through a bearing member l tiltably secured to the back of the plate 3 somewhat below its upper edge. The rod I5 can thus be reciprocated to cause movement of the crank l, the plate 3 having a verticai slot i? through which the roller and the lower end portion of the crank may swing outwardly. As shown, the bearing member i6 is provided with pins i8 entering into suitable openings or slots 32 in brackets forming part of a U-shaped piece i9 afiixed to the back of the plate 3. rThe slots 32 may extend upwardly from the lower ends of the brackets, thereby permitting the bearing member to be taken out when it becomes worn, and replaced by a new one. It is, however, normally held in position to permit only tilting movement thereof, by a compression spring 2li encompassing the r d I5 and reacting between the bearing member i5 and a collar 2l aiiixed near the lower end of the rod. The collar 2l is preferably in threaded engagement with the rod S5, so that its turning permits of an adjustment of the spring cornpression. It is desirable that this adjustment be made from the outside of the window frame and without necessitating a removal of the sash or sash-holding mechanism.. Accordingly, as shown in Figure 6, I may provide the collar 2i with spaced apertures 22, which become accessible from the outside of the window frame by merely removing a screw closure 23 normaliy kept in the aperture 24 formed through the plate 3 im.- mediately in front of the collar 2l. Withthe closure 23 removed, it is possible to insert a rod, screw driver, or other tool into the apertures 22 and to turn the collar 2l for the purpose of either increasing or reducingr the compression of the spring 2li. The spring tends to cause the rod l5 to translate downwardly, thereby forcing the roller I3 to swing outwardly through the opening l? in the plate 3.

The roller i3 is lengaged within a groove in the edge of the corresponding sash stile thereby serving to minimize the friction encountered in raising or lowering the sash. It is advantageous that each groove 25 be of gradually increasing depth from the upper edge of the sash to its lower edge, as this means that the spring-pressed roller will constantly tend to raise the sash and to overcome the effect of gravity thereupon. To the base of each groove 25 is preferably fastened a suitabley metal strip 2i, which furnishes a smooth, wear-resistant surfacey for the roller i3.

When the sash is in its fully lowered position, as shown in Figures l and 3, the roller i3 is engaged within the groove 25 at its upper end, which is of slight depth, so as to permit removal of the sash in a manner presently to be described. With the sash in its fully raised position, as shown in Figure 4, the roller i3 is swung outwardly and is engaged within the groove 25 at its lower end of maximum depth. The tiltable bearing i@ permits the rod I5 to move freely from its substantially vertical position shown in Figure 3 tc the inclined position shown in Figure 4.

The compression of the spring 2 is preferably adjusted so as to counter-balance the effect of gravity and thus hold the sash in any desired raised position. As already indicated, the compression cf the spring and its counter-balancing action may be accurately and quickly adjusted by turning the collar 2|, which is accessible from the outside of the window frame. Unless the holding mechanism were provided with means for maintaining the roller i 3 in its fully retracted position so as not to interfere with the sash, it would be exceedingly diilicult to effect a removal of the sash without disturbing the sash-holding mechanism, on account of the comparatively heavy compression necessary in the spring 20 for overcoming the weight of an ordinary window sash.

The construction and arrangement forming the subject matter of the invention are such as t0 enable the counter-balancing unit to be made inoperative so that when installed it will not interfere with the initial installation of the sash and any subsequent removal and replacement of the sash. This involves a retraction of the roller I3 until it does not project beyond the outer surface of the anchor plate 3.

To this end, the rod I5 is provided in its upper end with an opening 23, and the bracket or anchor plate 3 is provided with a threaded open- 2 in which an adjusting element such as the screw is disposed. When the sash is brought to its substantially fully lowered position, as seen in Figures 1 and 3, the roller I3 is forced farther and farther into the space 5 behind the jamb, thus rotating the bell crank lever 'I clockwise and raising the rod I5 until its opening 28 is slightly out of axial alignment with the screw 30, the opening 28 being so arranged that its upper side is in the path of movement of the conical end of the screw. As the screw 30 is rotated so as to move toward the rod I5, the conical end of the screw engages in the opening 28 and cams the rod upward, thus causing the crank 'l to rotate clockwise as seen in Figures l and 3 to such an extent as to withdraw the roller I3 until it does not project outwardly beyond the outer surface of the plate 3.

It will be observed that only a slight raising movement of the rod I 5 by the screw 30 is required to cause a substantial movement of the roller l5. This is due to the fact that when the pin I4, which turns about the pivot 8 as a center, is located adjacent its zenith, it moves a` substantial distance circumferentially although its vertica distance from the pivot 8 is changed only slightly. This is illustrative of the wellknown principle of harmonic motion. The axle l2 of the roller I3, because of its greater radius, moves throughout a somewhat greater arc than the pin I 4, and because of its rotation adjacent its zenith, moves laterally a distance almost equal to its arcuate movement and certainly sufliciently to draw the roller clear of the sash I.

Viewing Figure 3, it is clear that the rod I5 need be raised only a small fraction of the amount by which the roller I3 projects outwardly, in order to fully retract the roller.

As will be evident from the drawing, the spring 2i? is expanded as the sash I is raised from its lowered position oi Figure 3 to its upper position of Figure 4, wherein the spring is substantially longer than in Figure 3. Since the pressure exerted by the spring varies directly with its displacement due to load, obviously the pressure exerted by the spring 2i? in Figure 4 is substantially less than in Figure 3. Were the pressure which is transmitted to the roller i3 substantially variable with that of the spring, the gravityovercoming component of that pressure on the sash would correspondingly vary, and such circumstances would result in instability of the sash at one or both of its extreme positions and possib-ly at intermediate positions, thereby seriously impairing the value of the device.

The invention therefore embodies means for rendering the pressure between the roller I3 and the bearing strip 2l of the sash substantially constant for practical purposes for the range of movement necessary. To this end, the parts are arranged so that the torque about the pivot 8 through the desired range due to the varying forces exerted by the spring 2i] is substantially constant. This is accomplished by so arranging the rod I relative to the upper arm or the bell crank lever 'I that as the rod i5 is lowered, thus allowing the spring to expand and exert less pressure, the torque arm, that is, the shortest distance from the axis of the rod I5, extended downwardly, to the axis of the pivot i), increases. The increase in the torque arm is proportional or at least approximately proportional to the decrease in spring pressure, so that the pressure between the roller I3 and the sash I is practically uniform notwithstanding the different positions that may be occupied by the sash.

It is to be observed that the pressure from the roller I3, in addition to overcoming the gravity on the sash I, results in the setting up oi (a.) static friction which is of sufficient magnitude to prevent movement of the sash merely by virtue of any excess of either the sash weight or the coun.- terbalancing force, and to hold the sash in the desired position until overcome by external force as of a person, and (b) rolling friction which prevents too precipitate movement of the sash.

In addition to those advantages enumerated, it will be appreciated that the stile edges of a window sash forming part of the construction of the present invention are preserved tight against the jambs of the window frame, because frictional wear on these surfaces through the continued upward and downward movement of the sash is minimized. This means that air currents and/ or dust will not tend to leak past the stile edges into the interior of a building wherein my window construction is employed. Again, the various moving parts, including the roller, of my sashholding mechanism are completely concealed, thereby giving the window structure a neat appearance, as well as obviating accidental injury to these parts or to any one operating the window.

I claim:

1. A sash balancing unit comprising a bracket member having means for securing the same to a jamb of a window frame, a lever pivoted to the bracket member and provided with means arranged to project outwardly beyond the jamb, when the unit is properly mounted, so as to engage the juxtaposed stile of a sash, a bearing member, one of said members having trunnions and the other member having slots for receiving said trunnions, whereby the members may be readily assembled and the bearing member may pivot relative to the bracket member, a part pivoted to the lever and telescoping said bearing member, and a spring compresed between said bearing member and part so as to hold the members in assembled relation and urge the second means against the stile of the sash.

2. A sash-balancing device adapted to be mounted on one of a pair of relatively movable parts and including a spring-pressed member for pressing against an inclined track in a groove in the other part and adapted to be forced from the groove by progressively less` deep portions of the track, and means included in said device for retracting and xing the member out of the groove to enable the parts to be assembled and disassembled. n y

3. In a sash-balancing device, a lever mounted on a support, a roller carried by the lever and adapted to engage a ramp of a relatively movable part, a member pivoted to the lever and slidably engaged with a relatively stationary part of the device so as to constitute with the lever substantially a crank and connecting rod assembly, and a spring for pressing the roller against the ramp, said spring being operatively connected between said lever and said part oi the device so that as the spring is progressively stressed by engagement of the roller with progressively shallower portions of the ramp the torque arm at which the spring acts is progressively reduced and vice versa.

4. In a sash-balancing device, a lever mounted on a support adapted to be carried by one of a pair of relatively movable parts, a roller carried by the lever for engaging a ramp in a groove in the other part, a rod pivoted to the lever and slidably received by the support, a spring under stress and telescoped with said rod between the support and the lever and arranged so as to urge the roller against the ramp to counterbalance the sash and be stressed by engagement of the roller with less deep portions oi the ramp, and means arranged to cooperate with said rod so as to retract the roller to enable the sash to be removed and installed.

5. In a sash-balancing device, a lever mounted on a support adapted to be carried by one of a pair of relatively movable parts, a roller carried by the lever for engaging a ramp in a groove in the other part, a rod pivoted to the lever and slidably received by the support, a spring under stress and telescoped with said rod between the .support and the lever and arranged so as to urge the roller against the ramp to counterbalance the sash and be stressed by engagement of the roller with less deep portions of the ramp, and cam means operative when the roller is at the shallow part of the ramp for retracting the roller against th-e action of the spring to enable the sash to be removed and installed.

6. A sash-balancing device comprising a support, a lever pivoted tothe support and provided with means arranged to project outwardly beyond the support, when the unit is properly mounted, for engaging with a member between which and the support thereis to be relative movement during such engagement, a part pivoted to the lever and telescopically engaged with the support, a spring under stress between said support and part so as to hold them in assembled relation and urge said means against the member, means for varying the stress of said spring without disturbing the engagement between said means and said member and means for retracting the first means to enable the sash to be installed and removed.

7. An assembled pair of upwardly extending relatively movable sash and frame members, one of which has an inclined track forming the bottom of a groove extending in the general direction of relative movement of the members, and the other having a spring pressed part for engaging the track to balance the movable member against gravity, the track, because of its inclination, serving to force said part outwardly relative to the groove upon engagement of said part with progressively less deep portions of the track, and retaining means for xing said part out of the groove to enable the members to be assembled and disassembled.

8. In an assembly comprising relatively movable sash and frame members, one of which has an inclined track forming the bottom of a groove extending in the general direction of relative movement of the members, a balancing device mounted on the relatively stationary member, said device including a spring pressed member engageable with the track under spring pressure to balance the weight of the movable member and movable outwardly relative to the groove against the spring pressure, and retaining means included in said device for fixing said member out of the groove to enable the members to be assembled and disassembled, said means being disposed at an edge of the relatively stationary member and being shielded by the relatively movable member except when the relatively movable member is adjacent one limit of its movement.

9. A sash balancing device adapted to be mounted on one of a pair of relatively movable parts and including a member for exerting a counterbalancing pressure on a ramp on the other part, a spring for pressing said member against the ramp and arranged to be placed under increasing stress by progressively less deep portions of the ramp, and means, included in said device, affording a torque arm Varying directly with such stress to such an extent as to substantially compensate for the increased spring stress.

l0. In a sash balancing arrangement for sliding sashes, wherein the sash is provided with a stile portion having non-parallel relation with the stile of a frame, movable means for engaging said non-parallel stile portion for an appreciable portion thereof in the normal sliding movements of the sash, means for causing engagement of said movable means with said sash stile portion, the second means exerting a force whose magnitude varies with the respective positions 0f said sash in said frame, and means for coupling said movable means and said second means for automatically substantially neutralizing the variations in the magnitude of said force.

l1. In a sash balancing arrangement for sliding sashes, wherein the sash is provided with a stile portion having non-parallel relation with a frame stile, movable means for engaging said non-parallel sash stile portion for an appreciable portion thereof in the normal sliding movements o the sash, spring means for causing engagement of said movable means with said sash stile portion, the second means exerting a force Whose magnitude varies with the respective positions of said sash in said frame, and meanshaving a variable leverage for coupling said movable means and said second means for automatically substantially neutralizing the variations in the magnitude of said force.

l2. A sash balancing device adapted to be mounted on one of a pair of relatively movable parts and including a member adapted to exert a counterbalancing pressure on a ramp on the other part, a spring for pressing said member against the ramp and arranged so as to be placed under increasing stress by progressively less deep portions of the ramp, and means included in said device and associated with said spring and member for maintaining a substantially invariable pressure of said member against said ramp independently of the position of said member on said ramp.

13. A sash balancing device adapted to be mounted on one of a pair of relatively movable parts and including a member adapted to exert a counterbalancing pressure on a ramp on the other part, a spring for pressing said member against the ramp and arranged so as to be placed under increasing stress by progressively less deep portions of the ramp, means included in said device and associated with said spring and member for maintaining a substantially invariable pressure of said member against said ramp independently of the position of said member on said ramp, and means for adjusting the spring to enable the device to counterbalance sashes of different weights.

14. An assembled pair of upwardly extending relatively movable sash and frame members, one of which has an inclined track forming the bottom of a groove extending in the general direction of relative movement of the members, and the other having a part for engaging the track, a spring for pressing said part against the track and arranged tobe placed under increasing stress by engagement of said part with progressively less deep portions of the track, means associated with said spring and track for maintaining a substantially invariable pressure of said part against Said track independently of the position of said part on said track, and means for adjusting the spring to enable the device to counterbalance sashes of dilerent Weights.

l5. An assembled pair of upwardly extending relatively movable sash and frame members, providing at cooperative stiles thereof an inclined track forming the bottom of a groove in one member andk extending in the general direction of relative movement of the members, a gravity counterbalancing pressure device on the other member, said device including a part for engaging the track, a spring for pressing said part against the track and arranged to be placed under increasing stress by engagement of said part with progressively less deep portions of the track, and means included in said device and associated with said spring and track for maintaining a substantially invariable pressure of said part against said track independently of the position of said part on said track.

ABRAHAM SCHNIIZLER. 

